Various methods for the detection and determination of gases and vapors are known, such as, test tube methods which require a separate test tube for each test and mass spectral analysis which requires expensive equipment. Although mass spectral analysis is a very accurate and precise method such high precision and accuracy is often not necessary for such measurements.
Less expensive and hitherto known methods employ chemically sensitive sensors such as metal spirals or metal oxide semiconductors which can only be used at high temperatures and are only useful for measuring a few gases or vapors, e.g., oxygen in automobile exhaust, relative humidity, flue gas, or the determination of hydrogen or oxygen.